Mold/mildew on plywood eaves - how to remove and stop?

This is a first time post, I would really appreciate any ideas or thoughts people may have.

I bought my house 2 years ago and the prior owner did a lot of work and redid the exterior siding and roof including the eaves. The plywood under the eaves is unfinished which I think is part of the problem and encourages the growth. At first I didn’t notice any mold/mildew but last year there was a little bit and now it has spread and gotten worse. I think the unfinished plywood is encouraging the growth. I have roofline passive vents and I don’t see any issues in the attic.

So what is the best way to clean up the mold/mildew and then stop it from coming back?

After doing some research, my first thought was to use a mixture of bleach and water (about 1 part bleach to 5 parts water) to kill the spores and then scrub and wash it off. But I don’t want it to come back so I was thinking about putting a polyurethane finish on.


You want a paint specialist for this.

You are looking for a professional painter.

Some neat products to check out are: ShockWave (it’s used for mold remediation). There are many biocides out there that will kill everything under the sun. If that area was cleaned and painted or poly coated it should go away.

It’s the same thing I’m thinking how a deck gets mildew spots on it. they come off with deck cleaner and all is good to go stain it.

A pro painter should know what to do.

My quick & dirty fix to mould is scrubbing with borax. This is a potent antifungal. You can also thin latex paint with dissolved borax, and paint this on the affected area. Borax and latex is also a fire retardant (latex paint is used as an inhibitor on solid rocket motor grains by some hobbyists). I am not a roofer, but you might find this workable in your situation.